1. Field of the Invention
The present invention relates to a side protective moulding for automobiles (hereinafter referred to as the side moulding) for protecting an automobile body side surface, chiefly a door, from impacts in case of contact with an adjacent motor vehicle, wall, etc.
2. Description of the Related Art
The side moulding, as shown in FIG. 13, is a resin or rubber moulding mounted on the body (mainly a door 14) of an automobile 12.
The side moulding 50 must satisfy the following requirements to accomplish its purpose.
From viewpoint of function:
(1) The side moulding 50 must protrude sideward (outward) from a body 14 for the purpose of protecting the body 14 in case of accidental contact with an adjacent motor vehicle, wall, etc.
(2) The side moulding 50 must have so great a strength as to withstand a certain degree of impacts. If the side moulding 50 is deformed with impacts, the general outside appearance of the automobile will be deteriorated.
From viewpoint of decoration (outside appearance):
(3) The outside appearance of the side moulding 50 must be elegant. The side moulding 50 is a part to be installed on the outside of the automobile 12, and therefore if its surface is distorted, the general appearance of the automobile will be impaired.
From viewpoint of economics:
(4) The side moulding 50 must be of light weight and a manufacturing cost thereof must be low, which are based on the economics of manufacture demanded for the automobile 12, and on cost reduction common to every field of manufacture.
As a prior art side moulding, as shown in FIG. 5(b), there is a moulding using a metallic core of a C-shaped cross section covered with a flexible resin 54 such as non-rigid PVC etc.
This side moulding 56 is so designed as to be attached by fasteners such as clips to the body 14 of the automobile 12.
As another prior art side moulding, as shown in FIG. 5(c), there is a hollow moulding moulded of elastomer by a blow moulding process. This side moulding 58 is designed to be attached to the body 14 of the automobile 12 by the use of a double-coated adhesive tape or an adhesive.
A further another prior art moulding has a pair of ribs 62, 62 integrally formed on the back side of a protruding part 61 projecting to the side of the side moulding 60 as shown in FIG. 12.
In moulding the side moulding by an injection moulding process, generally a moulding thickness is set to about 2 to 4 mm to obtain better resin fluidity, whereby there will hardly occur a sink mark and a flow mark in the surface of the side moulding. It, therefore, is desirable that the protruding part be about 2 to 4 mm thick.
The protruding part 61 of the side moulding 60 is sometimes protruded over the thickness T of the protruding part 61 as shown in FIG. 12. In such a case, the rib 62 is integrally formed on the back side of the protruding part 61 to hold the protruding state by the rib 62. Moreover it is desirable that the protruding part 61 be apart from the body 14 of the automobile for the purpose of protection of the body. Most of the ribs 62, therefore, are comparatively long.
Furthermore, as another prior art side moulding, there is employed a flexible resin or rubber solid side moulding.
The prior art side mouldings 56 and 58 shown in FIG. 5(b) and 5(c), being off the automobile body at the back side of the most sideward protruding part and not reinforced, are liable to yield to impacts from outside. Providing that the body 14 contacts a wall etc. during travel or a door of an adjacent automobile contacts the side mouldings during parking, the side mouldings 56 and 58 will be easily deformed. If the side mouldings 56 and 58 are considerably deformed by an impact, not only the side mouldings 56 and 58 but the body 14 itself are injured.
In the meantime, increasing the thickness of the metallic core 52 and the resin 54 may be suggested for the purpose of improving their rigidity, but such a means is impractical because it will increase weight and manufacturing cost. Especially the increased thickness of resin will allow occurrence of sink marks in the Surface of the side mouldings 56 and 58 due to a difference in the rate of cooling, thereby impairing a decorating function.
The prior art side moulding 60 shown in FIG. 12 is produced by an injection moulding process. The rib 2 is a moulded portion ejected from a die, requiring a draft .alpha. for ejection. Generally, the draft is of the order of 1 to 2 degrees. The longer the rib 62, the thicker the root of the rib 62 becomes because of the draft provided. Therefore, there occurs a sink mark in the surface of the side moulding 60, resulting in impaired decorating function.
If the thickness of the rib 62 is reduced in an attempt to prevent the occurrence of a sink mark in the side moulding 60, the rib 62 will become unable to withstand an impact, failing in improving the impact strength of the side moulding 60.
Furthermore, decreasing the thickness of the rib 62 will give an adverse effect to resin fluidity, resulting in unsmooth flow of resin into the rib-moulding part of the die. The rib, therefore, is likely to be moulded in a defective shape, failing in contributing to improving the impact strength of the side moulding.
Furthermore, a pair of ribs are not mutually connected at the forward ends, and therefore if an impact is applied obliquely to the side moulding, the side moulding tends to slide laterally with respect to the automotive body 14. The ribs, therefore, can not withstand the oblique impact.
Furthermore, the prior art flexible resin or rubber solid side moulding is heavy and expensive.